Constant and variable-flow engine



April 1954 E. c. KIEKHAEFER 2,675,790

CONSTANT AND VARIABLE-FLOW ENGINE COOLANT SYSTEM Filed Dec. 1, 1950 24 I 3 I o [3 t I Q u .6 I

IN VEN TOR.

291(0))? eys Patented Apr. 20, 1954 CONSTANT AND VARIABLE -FLOW ENGINE COOLANT SYSTEM Elmer C. Kiekhaefer, Cedar-burg, Wis.

Application December 1, 1950, Serial No. 198,700

2 Claims.

This invention relates to water cooling systerms for certain types of engines and particularly to providing under controlled pressure at different rates of flow to different parts of the engine at various speeds.

The invention provides an engine having two or more coolant chambers adapted to receive coolant under nominal pressure at varying rates of flow wherein the impact of the coolant flowing to one or more of said chambers having restricted outlets provides a relatively uniform flow of coolant under pressure therethrough while the rate of flow through the other chambers varies with the rate of delivery of the coolant.

A principal object of the invention is to provide controlled, positive pressure flow through the coolant chambers at the desired different rates varying with the total coolant delivery or speed of the engine.

A further object is to circulate coolant from a single delivery means at nominal pressure through two or more chambers at different pressures and rates of flow and provide for discharge of the coolant through a single passage.

A more particular object is to provide a variable fiow of coolant under nominal pressure through one chamber and a relatively more constant flow of coolant under pressure through another chamber.

These and other objects and advantages will be more fully set forth. in the following descrip tion of a preferred embodiment of the invention as illustrated in the accompanying drawing.

In the drawing:

Figure 1 is a side elevation of the engine of an outboard motor with portions thereof broken away and sectioned;

Fig.2 is a transverse vertical section taken through the engine exhaust chamber and coolant chambers and showing the upper ends of the engine cylinders in elevation;

Fig. 3 is an enlarged detail view of the coolant delivery pipe and passages to the two separate coolant chambers; and

Fig. 4 is a diagrammatic illustration of the engine coolant system.

The engine of an outboard motor is supported on the upper end of the drive shaft housing 2. The drive shaft 3 from engine I extends downwardly through housing 2 to the underwater propeller unit, not shown. The pump 4 shown diagrammatically in Fig. 4 is disposed underwater so as to be in constant supply of water for delivery to the engine I for cooling purposes. Pump 4 is preferably of a type which does not develop more than a nominal pressure at any delivery and should be of a capacity which provides adequate cooling at all speeds of the engine. The pump 4 is driven by engine I through drive shaft 3 and operates at the same speed as the engine with a delivery rate substantially proportionate to the speed of the engine. The pipe 5 from pump 4 extending in housing 2 up to the engine is carried at the upper end in the boss 6 of the housing for delivery of water to the engine as will be described.

Engine l includes the cylinder block i which is provided with cavities '8 and 9 on opposite sides thereof. The cavity 50 opens to the rear of block 1 and is closed by plate H to provide a coolant chamber which encloses the upper ends of the cylinders I2. Cavity 8 is adapted to receive the exhaust gases of cylinders l2 and opens downwardly of block 1 into the upper end of drive shaft housing 2. The plate l3 closes the side opening of cavity 8 and the cover I4 over plate I3 is recessed as at Is to provide a space therebetween adapted to receive a flow of coolant as will be described. The plate [6 on the opposite side of engine block I closes cavity 9 which requires a relatively uniform circulation of coolant for optimum engine operation throughout widely varying conditions. In engine l cavity 9 overlies the transfer passages, not shown, through which the fuel mixture is delivered to the cylinders for compression and combustion.

The lower end of block I adjoins boss 6 of housing 2 carrying pipe 5 and is provided with the groove I? and the O-ring seal ls therein which latter engages the upper face of boss 5. The passage I 9 from cavity 9 opens from the bottom of block 1 within seal IB and registers with the upper open end of pipe 5.

Passage 211 communicates with passage l9 and opens into the lower end of chamber l0. Passages I9 and 20 may be variously formed or drilled in block I to provide the inanifolding of the coolant as will be described. Passage 2%, as shown, is drilled from the side of block I through passage I9 and into chamber I0 and is closed at the end opening from the side of the block by plate [6.

The passage 2! in block 1 from the upper end of cavity 9 opens into the upper end of chamber l0 and passage 22in block 1 from the upper end of chamber In through holes 23 in plate It opens into the upper portion of recess W. The drilled drain opening 24 from the bottom of recess l5 opens from block 1 into the upper open end of drive shaft housing 2.

In the operation of the motor, water is delivered by pump 4 through pipe 5 to the engine block. The water delivered through passages 19 and 263 to chambers 9 and I0 fills the chambers to the level of passages 2| and 22. From chamber 5 the water traveling through passage 2! passes through the upper end of chamber Ii! and with the water therein travels through passage 22 into recess Hi. The water is discharged from recess l5 through drain passage 24 into housing 2 from which it leaves the motor through an underwater opening, not shown.

Passage 20 is angularly disposed with respect According to the invention, the rate of cira culation of water through chamber it! varies approximately with the delivery rate of pump 4 and the speed of engine 1 while a positive pressure circulation of water through chamber 8 is efiected at a rate which varies only slightly at various speeds of engine I.

The water traveling upwardly through pipe and passage I 9 with a predetermined velocity and a corresponding momentum is directed into cavity 9 so that the impact of the water, by reason of the restricted outlet passage 2!, effects and maintains a positive pressure condition in cavity 9.

The amount of water which passes throug cavity 9 is thus controlled by the predetermined size of passage 21 and the pressure effected by the impact of the water directed into the cavity. While this amount varies to a certain extent with the velocity referred to, a generally more flat rate obtains which corresponds with the cooling requirements at the corresponding speed of the engine and delivery rate of pump 4.

The water delivered by pump in excess of that passing through cavity 9 enters chamber is as described to effect cooling of cylinders 22.

This amount varies directly with the delivery rate of pump 4 less the amount passing through cavity 9, as described, and corresponds generallywith the required cooling of cylinders 12 at the corresponding speed of the engine.

At low speeds of engine 1 embodying the invention a relatively small amount of water passes through cavity 9 under positive pressure while most of the Water passes through chamber Hi to cool cylinders l2.

At high speeds the greater delivery rate of pump exceeds the increased requirements of chamber Hi and an increased percentage of the Water delivered in excess to the engine passes through cavity 9 to meet the increased coolant requirements of that part of the engine.

The circulation of the water through the engine at all times and at all speeds is effected entirely by pressure so that the predetermined rates of circulation are maintained irrespective of the relative temperatures of different parts or" the engine at different times and conditions of operation. 7

At low engine speeds adequate circulation or coolant through chamber I0 to'cool cylinders i2 is assured and relatively limited circulation of coolant under pressure eifected through cavity 9 will not over-cool the transfer passages or the adjacent part of the engine.

At high engine speeds the proportionately greater circulation of coolant under pressure effected through cavity 9 assures adequate cooling of the transfer passages necessary for efiicient engine operation.

If desired, the restricted passage 2! from cavity 9 can be made to openand to discharge the water directly from the engine without passing through chamber It or joining the water discharged therefrom in recess l5.

Means for providing a delivery of water other than a pump driven by the engine may be employed, and various other embodiments of the invention may be employed within the scope of the accompanying claims.

I claim:

1. In an engine having separate first and second coolant chambers and including pressure means operating with said engine for delivery of a coolant to said chambers at a rate approximately proportionate to the speed of operation of the engine, a restricted passage from said first chamber opening into said second chamber, a relatively unrestricted discharge opening from said second chamber, a supply passage con nected to said pressure means and opening into said first chamber at an end opposite said restricted outlet passage, and an alternate passage to said second chamber and-extending from said supply passage at a point spaced from said first chamber to supply coolant to said second chamber and divide the coolant supply of said pressure means between said first and second chambers, said alternate passage being correlated to said supply passage and disposed at an angle thereto whereby the flow inertia of the coolant in said supply passage maintains a pressure in said first chamber in cooperation with said restricted passage and the proportionate flow of nt through said first and second chambers ied upon change of engine speed.

In an engine having separate first and second coolant chambers and including pressure means operating with said engine for delivery of a coolant to said chambers at a rate approximately proportionate to the speed of operation of the engine, a restricted passage from said first chamber for discharge of the Water therefrom at a predetermined rate, a relatively unrestricted discharge opening from said second chamber, a supply passage connected to said pressure means and opening into said first chamher at an end opposite said restricted outlet passage, and an alternate passage to said second chamber and extending from said supply passage at a point spaced from said first chamber to supply coolant to said second chamber and divide the coolant supply of said pressure means between said first and second chambers, said alternate passage being correlated to said supply passage and disposed at an ange thereto whereby the flow inertia of the coolant in said supply passage maintains a pressure in said first chamber in cooperation with said restricted passage and the proportionate flow of coolant through said first and second chambers is varied upon change of engine speed.

References Cited in the file 51 this patent UNITED s'rarns PATENTS Great Britain ag. 2 ,1919 

